The incremental value of Mycobacterium tuberculosis trace nucleic acid detection in CT-guided percutaneous biopsy needle rinse solutions for the diagnosis of tuberculosis.

Introduction: Tuberculosis (TB) diagnosis still faces challenges with high proportion of bacteriologic test negative incidences worldwide. We assessed the diagnostic value of digital PCR (dPCR) analysis of ultramicro Mycobacterium tuberculosis (M.tb) nucleic acid in CT-guided percutaneous biopsy needle rinse solution (BNRS) for TB. Methods: BNRS specimens were consecutively collected and total DNA was purified. The concentrations of M.tb-specific IS6110 and IS1081 were quantified using droplet dPCR. The diagnostic performances of BNRS-dPCR and its sensitivity in comparison with conventional tests were analyzed. Results: A total of 106 patients were enrolled, 63 of whom were TB (48 definite and 15 clinically suspected TB) and 43 were non-TB. The sensitivity of BNRS IS6110 OR IS1081-dPCR for total, confirmed and clinically suspected TB was 66.7%, 68.8% and 60.0%, respectively, with a specificity of 97.7%. Its sensitivity was higher than that of conventional etiological tests, including smear microscopy, mycobacterial culture and Xpert using sputum and BALF samples. The positive detection rate in TB patients increased from 39.3% for biopsy AFB test alone to 73.2% when combined with BNRS-dPCR, and from 71.4% for biopsy M.tb molecular detection alone to 85.7% when combined with BNRS-dPCR. Conclusion: Our results preliminarily indicated that BNRS IS6110 OR IS1081-dPCR is a feasible etiological test, which has the potential to be used as a supplementary method to augment the diagnostic yield of biopsy and improve TB diagnosis.

CAS Landslide Dataset: A Large-Scale and Multisensor Dataset for Deep Learning-Based Landslide Detection.

In this work, we present the CAS Landslide Dataset, a large-scale and multisensor dataset for deep learning-based landslide detection, developed by the Artificial Intelligence Group at the Institute of Mountain Hazards and Environment, Chinese Academy of Sciences (CAS). The dataset aims to address the challenges encountered in landslide recognition. With the increase in landslide occurrences due to climate change and earthquakes, there is a growing need for a precise and comprehensive dataset to support fast and efficient landslide recognition. In contrast to existing datasets with dataset size, coverage, sensor type and resolution limitations, the CAS Landslide Dataset comprises 20,865 images, integrating satellite and unmanned aerial vehicle data from nine regions. To ensure reliability and applicability, we establish a robust methodology to evaluate the dataset quality. We propose the use of the Landslide Dataset as a benchmark for the construction of landslide identification models and to facilitate the development of deep learning techniques. Researchers can leverage this dataset to obtain enhanced prediction, monitoring, and analysis capabilities, thereby advancing automated landslide detection.

Dual disasters: Seismic evacuation decision-making during COVID-19 lockdown: A case study of Luding earthquake, Sichuan Province.

Although there is a growing body of literature on the COVID-19 pandemic and the implemented strategies that have imposed additional risks in tackling emergencies by increasing socio-economic vulnerabilities, studies on human evacuation behavior during lockdowns are lacking. This paper contributes to evacuation and emergency research by examining seismic evacuation decision-making by surveying the areas affected by the Luding earthquake on 5 September 2022, when most parts of Sichuan province were experiencing strict pandemic restrictions. Using these data and per the emergency evacuation decision-making mechanism, we developed six hierarchical series of logistic regression models. Our major results suggest that 1) Socio-demographic parameters have shown different correlations with the study's dependent variables in each stage of those hierarchical models, 2) Respondents at home at the time of the earthquake were more likely to identify the earthquake risk than those who stayed outdoors; the former group showed less willingness to evacuate, 3) Rural residents have perceived higher earthquake risks than urban residents, and 4) Loss of job, change in income due to COVID-19 restrictions, and difficulty accessing daily supplies during the lockdown affected the residents' risk assessment and evacuation decision-making negatively. Insights into these aspects are expected to contribute to a better understanding of evacuation behavior during double disasters by modifying emergency response regulations and providing the residents with information about emergencies during pandemic restrictions.

Neural network-based model for evaluating inert nodules and volume doubling time in T1 lung adenocarcinoma: a nested case-control study.

Objective: The purpose of this study is to establish model for assessing inert nodules predicting nodule volume-doubling. Methods: A total of 201 patients with T1 lung adenocarcinoma were analysed retrospectively pulmonary nodule information was predicted by an AI pulmonary nodule auxiliary diagnosis system. The nodules were classified into two groups: inert nodules (volume-doubling time (VDT)>600 days n=152) noninert nodules (VDT<600 days n=49). Then taking the clinical imaging features obtained at the first examination as predictive variables the inert nodule judgement model >(INM) volume-doubling time estimation model (VDTM) were constructed based on a deep learning-based neural network. The performance of the INM was evaluated by the area under the curve (AUC) obtained from receiver operating characteristic (ROC) analysis the performance of the VDTM was evaluated by R2(determination coefficient). Results: The accuracy of the INM in the training and testing cohorts was 81.13% and 77.50%, respectively. The AUC of the INM in the training and testing cohorts was 0.7707 (95% CI 0.6779-0.8636) and 0.7700 (95% CI 0.5988-0.9412), respectively. The INM was effective in identifying inert pulmonary nodules; additionally, the R2 of the VDTM in the training cohort was 0.8008, and that in the testing cohort was 0.6268. The VDTM showed moderate performance in estimating the VDT, which can provide some reference during a patients' first examination and consultation. Conclusion: The INM and the VDTM based on deep learning can help radiologists and clinicians distinguish among inert nodules and predict the nodule volume-doubling time to accurately treat patients with pulmonary nodules.

Effect of Post-Weld Heat Treatment on Microstructure and Fracture Toughness of X80 Pipeline Steel Welded Joint.

In the current study, post-weld heat treatment (PWHT 580 °C) was used for an X80 pipeline steel-welded joint, and the fracture toughness of the welded joint was investigated using a crack tip opening displacement (CTOD) test. The relationship between microstructure evolution and fracture toughness is also discussed in this study. The results showed that the weld center mainly consisted of acicular ferrite (AF). The subcritical heat-affected zone (SCHAZ) consisted of a large amount of fine polygonal ferrite and some AF, and it maintained the rolling state of the base metal. The microstructure of the coarse-grained heat-affected zone (CGHAZ) was composed of granular bainite (GB) and M/A constituents, the latter of which decreased after the PWHT. The CTOD values of the weld center were in the range of 0.18-0.27 mm, while those of the CGHAZ were in the range of 0.02-0.65 mm. A brittle fracture occurred in the CGHAZ for both the as-welded and PWHT samples; the CTOD values were 0.042 mm and 0.026 mm, respectively. The CTOD values of the SCHAZ's location were in the range of 0.8-0.9 mm. The PWHT did not deteriorate the microstructure of the CGHAZ and had little influence on the fracture toughness of the X80 pipeline steel-welded joint; it ensured the fracture toughness of the welded joints and reduced the welding residual stress.

Key Technologies of Physical and Virtual Test Rig for Railway Freight Car body.

On the one hand, considering that the traditional fatigue method of railway freight cars is based on damage as a parameter, the influence of stress waveform cannot be considered. On the other hand, physical experiments have the characteristics of lag, long period, and high cost. The full-scale physical test and virtual test of car body are carried out. First of all, the data processing method of small deletion and the inverse problem load acquisition method based on data to data are proposed. Secondly, the dynamic stress calculation method with the bench as the boundary is proposed. Finally, taking the obtained load as the input of the physical and virtual bench, a new fatigue test method for simulating the running attitude of the car body line is completed. The acceleration RMS error of the C70E gondola body is less than 6%, the stress RMS is less than 13%, and the equivalent mileage is 3.125 million highway test results show that the car meets the life requirements of the car body. The inverse problem analysis results of virtual and physical tests are basically consistent, and the study of this method provides a basis for improving the fatigue reliability of freight car bodies.

Effect of H2S Corrosion on the Fracture Toughness of the X80 Pipeline Steel Welded Joint.

To analyze the causes and mechanisms affecting the fracture toughness of X80 pipeline steel welded joints against H2S, the fracture toughness of different zones of X80 pipeline steel welded joints in both air and saturated H2S solution was investigated. The fracture toughness of welded joints degraded significantly in the saturated H2S solution, where the crack tip opening displacement (CTOD) characteristic value in the coarse grain heat-affected zone (CGHAZ) and weld metal (WM) was only 8% and 12% of that in air, respectively. However, the sub-critical grain heat-affected zone (SCHAZ) showed better resistance to H2S corrosion, with the CTOD characteristic value reaching 42% of that in air. The resistance of the welded joint to H2S corrosion was sensitive to microstructures. The grain boundary ferrite (GBF) presented in WM, and the angle of grain boundary orientation in CGHAZ was not conducive to hindering crack propagation. Moreover, the formation of the resultant hydrogen cracks owing to the H2S corrosion also reduced the fracture toughness of the welded joint.

Increased Tuberculosis Incidence Due to Immunotherapy Based on PD-1 and PD-L1 Blockade: A Systematic Review and Meta-Analysis.

Objectives: In this study, we conducted a systematic review to determine tuberculosis (TB) incidence due to immunotherapy with programmed cell death protein-1 (PD-1)/PD ligand (PD-L1) blockade in cancer patients. Methods: We searched PubMed, Cochrance Library, Excerpt Medica Database (Embase), ClinicalTrials.gov, Chinese BioMedical Literature Database (CBM), China National Knowledge Infrastructure Database (CNKI), Wanfang and China Science and Technology Journal Database to identify studies between January 1, 2000 and April 30, 2021, on the reports of TB cases in patients treated with PD-1/PD-L1 blockade. Methodological quality of eligible studies was assessed, and random-effect model meta-analysis was performed to generate the pooled incidence estimate of TB cases in patients undergoing PD-1/PD-L1 therapy. Results: We initially identified 745 records, of which 27 studies ultimately met the inclusion criteria and were included in our meta-analysis. A total of 35 TB cases occurred among patients treated with PD-1/PD-L1 blockade. Nivolumab (51.4%) was the most frequently used PD-1/PD-L1 blockade for cancer treatment. In addition, pulmonary TB was the most common form of tuberculosis seen in 77.1% cases. Clinical outcomes were recorded in 18 patients, of whom 77.8% were cured or achieved remission, and 22.2% were died of TB. Pooled analysis determined that the TB rate in this population was 2,000 cases per 100,000 persons, and the estimated rate for TB associated with PD-1/PD-L1 blockade was 35 times higher than that in the general population. Conclusion: To conclude, our results demonstrate that the clinical use of PD-1/PD-L1 inhibitors significantly increases risk of TB reactivation. An extremely high mortality rate due to TB disease is noted in the patients with PD-1/PD-L1 blockade.

Experimental investigation of the creep behaviour of remoulded loess under different levels of compactness.

Generally, a loess high fill project will undergo a time-dependent deformation and settlement process for a long time after the initial fill. Understanding the creeping behaviour of compacted loess is an important part of determining the stability of a compacted loess foundation. To study the creep behaviour of remoulded loess under different levels of compactness, we performed triaxial shear and triaxial creep tests using Q2 loess specimens obtained from the new district of Yan'an city. Based on laboratory test results, the triaxial shear and creep characteristics of remoulded loess under different levels compactness are summarised. The regularity of instantaneous strain, creep strain, total accumulated strain and initial shear modulus were analysed and the relationship between the compactness and long-term strength of remoulded loess is provided. It was found that the remoulded loess becomes harder and its long-term strength increases with an increase in compactness. Furthermore, we propose a new creep model (HD), based on the hardening-damage mechanism, and have derived one-dimensional (1D) and three-dimensional (3D) creep equations based on this new creep model. This new creep model is flexible enough to fit the typical creep test curves of remoulded loess, while perfectly describing the tertiary creep stage. Finally, the sensitivity of the HD creep model parameters was analysed; the results indicate that the parameters denoted as α, γ, and ß significantly affect the morphological changes and various stage characteristics are represented by the creep curve.

Research on Damage Characteristics of Ultrasonic Vibration-Assisted Grinding of a C/SIC Composite Material.

C/SiC composites are the preferred materials for high temperature resistant (usually above 1500 °C) structural parts in aerospace, aviation, shipbuilding, and other industries. When this kind of material component is processed efficiently by grinding, the damage forms of fiber step brittle fracture and fiber pulling out are often produced on the machined surface/subsurface. The existence of these damage forms deteriorates the quality of the machine surface and may reduce the bending strength of materials to a certain extent. Therefore, it is very important to study the mechanism and the damage law of ordinary grinding and ultrasonic vibration-assisted grinding and take reasonable measures to restrain the machining damage. In this paper, the typical damage forms of C/SiC composites during the end and side grinding are explored. The surface and subsurface damage degree of C/SiC composites during grinding and ultrasonic vibration-assisted grinding were compared. The effects of different process parameters on material damage were compared and analyzed. The results show that the damage forms of ordinary grinding and ultrasonic grinding are basically the same. Compared with ordinary grinding, ultrasonic-assisted grinding can reduce surface damage to a certain extent and subsurface damage significantly.

Elevated Natural Killer Cell-Mediated Cytotoxicity Is Associated with Cavity Formation in Pulmonary Tuberculosis Patients.

Cavitation is a major pathological feature of pulmonary tuberculosis (TB). The study is aimed at investigating the mechanism of natural killer (NK) cells participating the cavity formation during Mycobacterium tuberculosis (MTB) infection. Human peripheral blood samples were donated by pulmonary TB patients with cavity or not. Real-time quantitative PCR and enzyme-linked immunosorbent assay were performed to analyze the expression of cytokines secreted by NK cells. And the cytotoxicity of NK cells was compared between two groups. Our data showed that NK cells were more abundant in cohorts of cavity. Increased abundance of granzyme A and granzyme B was observed in culture supernatants of NK cells isolated from cavitary TB patients, which also resulted in a higher level of nonviable MTB-infected monocytes. Our data firstly demonstrates that NK cells participate in cavity formation in pulmonary TB patients. The elevated level and increased cytotoxicity of NK cells accelerate the cavitary formulation.

Dynamic cfDNA Analysis by NGS in EGFR T790M-Positive Advanced NSCLC Patients Failed to the First-Generation EGFR-TKIs.

PURPOSE: Circulating cell-free DNA (cfDNA) level has been demonstrated to be associated with efficacy in first generation EGFR TKIs in non-small cell lung cancer (NSCLC). However, the role of dynamic cfDNA analysis using next-generation sequencing (NGS) in patients with subsequent third-generation EGFR TKIs remains unclear. METHODS: From 2016 to 2019, 81 NSCLC patients with EGFR T790M mutation either in tissue or plasma who received third-generation EGFR TKIs treatment were enrolled. CfDNA were sequenced by NGS with a 425-gene panel. The association of clinical characteristics, pretreatment, dynamic cfDNA and T790M level with outcomes in patients treated with the third-generation TKIs were analyzed. RESULTS: In univariate analysis, the median PFS of patients with undetectable cfDNA level during treatment was significantly longer than those with detectable cfDNA (16.97 vs. 6.10 months; HR 0.2109; P < 0.0001). The median PFS of patients with undetectable T790M level during treatment was significantly longer than those with detectable T790M (14.1 vs. 4.4 months; HR 0.2192; P < 0.001). Cox hazard proportion model showed that cfDNA clearance was an independent predictor for longer PFS (HR 0.3085; P < 0.001) and longer OS (HR 0.499; P = 0.034). The most common resistant mutations of the third-generation TKIs were EGFR C797S (24%). CDK6 CNV, GRIN2A, BRCA2, EGFR D761N, EGFR Q791H, EGFR V843I, and ERBB4 mutation genes may possibly be new resistant mechanisms. CONCLUSIONS: Patients with undetectable cfDNA during the third-generation EGFR TKI treatment have superior clinical outcomes, and dynamic cfDNA analysis by NGS is valuable to explore potential resistant mechanisms.

Very-High-Cycle Fatigue Behavior of Inconel 718 Alloy Fabricated by Selective Laser Melting at Elevated Temperature.

This study investigates the very-high-cycle fatigue (VHCF) behavior at elevated temperature (650 °C) of the Inconel 718 alloy fabricated by selective laser melting (SLM). The results are compared with those of the wrought alloy. Large columnar grain with a cellular structure in the grain interior and Laves/δ phases precipitated along the grain boundaries were exhibited in the SLM alloy, while fine equiaxed grains were present in the wrought alloy. The elevated temperature had a minor effect on the fatigue resistance in the regime below 108 cycles for the SLM alloy but significantly reduced the fatigue strength in the VHCF regime above 108 cycles. Both the SLM and wrought specimens exhibited similar fatigue resistance in the fatigue life regime of fewer than 107-108 cycles at elevated temperature, and the surface initiation mechanism was dominant in both alloys. In a VHCF regime above 107-108 cycles at elevated temperature, the wrought material exhibited slightly better fatigue resistance than the SLM alloy. All fatigue cracks are initiated from the internal defects or the microstructure discontinuities. The precipitation of Laves and δ phases is examined after fatigue tests at high temperatures, and the effect of microstructure on the formation and the propagation of the microstructural small cracks is also discussed.

Determining the optimal puncture site of CT-guided transthoracic needle aspiration biopsy for the diagnosis of tuberculosis.

BACKGROUND: The purpose of this study was to determine the optimal puncture site of computed tomography (CT)-guided transthoracic needle aspiration biopsy for the diagnosis of tuberculosis (TB) by the comparison of clinical and radiological characteristics of TB patients stratified to different histopathological results. METHODS: We retrospectively analysed the data of clinically diagnosed TB patients with negative laboratory results between July 2016 and June 2018. Biopsy specimens were obtained from patients for Ziehl-Neelsen (Z-N) staining and TB-DNA. RESULTS: For the 356 TB patients, the positive rate of TB-DNA was 70.9%, which was significantly higher than that of Z-N staining (46.4%, P<0.001). The positive rate of lesions from upper lobe (76.4%, 155/203) was significantly higher than that from lower lobe (63.1%, 89/141, P=0.008). The mean of ΔCT density for positive histologic group (12.84±6.81 HU) was lower than that for negative histologic group (28.32±9.82 HU, P<0.001). ROC curve analysis revealed that a density-based cut-off value of 20.5 HU should be set as the cut-off values for determining the optimal puncture site. CONCLUSIONS: Our data demonstrates that the molecular diagnostics has superiority over Z-N staining for detecting MTB from lung aspirates. The lung biopsies from upper lobe were more likely to yield positive histologic results than those from lower lobe. In addition, the enhancement of 20.5 HU by CT scans should be set as the cut-off values for determining the optimal puncture site that would facilitate an efficient diagnosis of pulmonary TB.

Combination of Percutaneous Lung Biopsy and Xpert MTB/RIF Ultra Enhances the Differential Diagnosis of Tuberculosis: A Prospective Cohort Study.

INTRODUCTION: To evaluate the value of the combination of computed tomography (CT)-guided percutaneous lung biopsy and Xpert MTB/RIF Ultra (Xpert-Ultra) in enhancing the differential diagnosis of tuberculosis. METHODS: Patients with lesions in the lungs for whom the differential diagnosis was difficult were prospectively and consecutively enrolled. Specimens collected by percutaneous lung biopsy were subject to Xpert-Ultra and histopathologic examination, respectively. RESULTS: Biopsy was successfully performed for 147 patients who were eligible for analysis, including 65 TB, 55 lung cancer and 27 other chronic infection cases. The sensitivity, specificity, positive predictive value and negative predictive value of Xpert-Ultra for TB diagnosis were 75.38% (49/65) and 95.12% (78/82), 92.45% (49/53) and 82.98% (78/94), respectively. Among patients with strong evidence for TB diagnosis (categorized as confirmed or probable TB cases), the overall positive rate of the Xpert-Ultra assay was 83.63% (46/55), which was much higher than for any reported sample type with negative smear test outcomes to date. Five rifampicin (RIF)-resistant cases were identified using the biopsy tissues. However, "trace" positive did not seem reliable for TB diagnosis with lung biopsy specimens; a 25.61% (21/82) "trace"-positive rate was acquired in the non-TB group. CONCLUSION: Percutaneous lung biopsy combined with Xpert-Ultra produced high sensitivity for culture-negative pulmonary TB patient diagnosis. "Trace" outcome might not be a reliable positive category for lung biopsy specimens. TRIAL REGISTRATION: ClinicalTrials.gov identifier, ChiCTR1900026412. Retrospectively registered on Oct 8th, 2019).

Research on Material Removal Mechanism of C/SiC Composites in Ultrasound Vibration-Assisted Grinding.

C/SiC composites are the preferred materials for hot-end structures and other important components of aerospace vehicles. It is important to reveal the material removal mechanism of ultrasound vibration-assisted grinding for realizing low damage and high efficiency processing of C/SiC composites. In this paper, a single abrasive particle ultrasound vibration cutting test was carried out. The failure modes of SiC matrix and carbon fiber under ordinary cutting and ultrasound cutting conditions were observed and analyzed. With the help of ultrasonic energy, compared with ordinary cutting, under the conditions of ultrasonic vibration-assisted grinding, the grinding force is reduced to varying degrees, and the maximum reduction ratio reaches about 60%, which means that ultrasonic vibration is beneficial to reduce the grinding force. With the observation of cutting debris, it is found that the size of debris is not much affected by the a p with ultrasound vibration. Thus, the ultrasound vibration-assisted grinding method is an effective method to achieve low damage and high efficiency processing of C/SiC composites.

Use of low-dose computed tomography to assess pulmonary tuberculosis among healthcare workers in a tuberculosis hospital.

BACKGROUND: According to the World Health Organization, China is one of 22 countries with serious tuberculosis (TB) infections and one of the 27 countries with serious multidrug-resistant TB strains. Despite the decline of tuberculosis in the overall population, healthcare workers (HCWs) are still at a high risk of infection. Compared with high-income countries, the TB prevalence among HCWs is higher in low- and middle-income countries. Low-dose computed tomography (LDCT) is becoming more popular due to its superior sensitivity and lower radiation dose. However, there have been no reports about active pulmonary tuberculosis (PTB) among HCWs as assessed with LDCT. The purposes of this study were to examine PTB statuses in HCWs in hospitals specializing in TB treatment and explore the significance of the application of LDCT to these workers. METHODS: This study retrospectively analysed the physical examination data of healthcare workers in the Beijing Chest Hospital from September 2012 to December 2015. Low-dose lung CT examinations were performed in all cases. The comparisons between active and inactive PTB according to the CT findings were made using the Pearson chi-square test or the Fisher's exact test. Comparisons between the incidences of active PTB in high-risk areas and non-high-risk areas were performed using the Pearson chi-square test. Analyses of active PTB were performed according to different ages, numbers of years on the job, and the risks of the working areas. Active PTB as diagnosed by the LDCT examinations alone was compared with the final comprehensive diagnoses, and the sensitivity and positive predictive value were calculated. RESULTS: A total of 1 012 participants were included in this study. During the 4-year period of medical examinations, active PTB was found in 19 cases, and inactive PTB was found in 109 cases. The prevalence of active PTB in the participants was 1.24%, 0.67%, 0.81%, and 0.53% for years 2012 to 2015. The corresponding incidences of active PTB among the tuberculosis hospital participants were 0.86%, 0.41%, 0.54%, and 0.26%. Most HCWs with active TB (78.9%, 15/19) worked in the high-risk areas of the hospital. There was a significant difference in the incidences of active PTB between the HCWs who worked in the high-risk and non-high-risk areas (odds ratio [OR], 14.415; 95% confidence interval (CI): 4.733 - 43.896). Comparisons of the CT signs between the active and inactive groups via chi-square tests revealed that the tree-in-bud, cavity, fibrous shadow, and calcification signs exhibited significant differences (P = 0.000, 0.021, 0.001, and 0.024, respectively). Tree-in-bud and cavity opacities suggest active pulmonary tuberculosis, whereas fibrous shadow and calcification opacities are the main features of inactive pulmonary tuberculosis. Comparison with the final comprehensive diagnoses revealed that the sensitivity and positive predictive value of the diagnoses of active PTB based on LDCT alone were 100% and 86.4%, respectively. CONCLUSIONS: Healthcare workers in tuberculosis hospitals are a high-risk group for active PTB. Yearly LDCT examinations of such high-risk groups are feasible and necessary.

[MR image analysis of 147 cases of meningeal tuberculosis].

OBJECTIVE: To investigate the MRI features of meningeal tuberculosis. METHODS: The MR images of meningeal tuberculosis were retrospectively analyzed in 147 patients who were clinically diagnosed from 2009 to 2014 years in our hospital, including 77 males, and 70 females. Their age ranged from 14 to 70 years, and the average age was(32 ± 13)years. All cases underwent MR plain scan and enhancement scan, and 26 cases underwent 3D TOF sequence and MRA vascular reconstruction. The characteristics of the morphological change, MR signal of meningeal lesions and the secondary changes were investigated for 56 cases of meningeal carcinomatosis due to lung cancer, including 29 males and 27 females. Their age ranged from 36 to 78 years old, and the average age was (58 ± 11)years. The MR imaging characteristics of meningeal lesions were compared with those of meningeal tuberculosis. Chi-square test and logistic regression analysis were used for count data analysis, and t-test was used for measurement data. P<0.05 was regarded as statistically significant. RESULTS: Among 147 cases of meningeal tuberculosis, 146 (99.32%) had involvement of the cerebral pia mater, 104 of the basal cistern, and 108 of the cistern of lateral fissure pools. Lesions located in fissura longitudinalis cerebri pool, convexity of brain and cerebellar back were found in 46, 35 and 17 cases, respectively. MRI findings in plain scan were normal in 11 patients, and abnormal in 136 cases. Thickening meningeal lesions with different degrees were shown in the abnormal cases, with irregular or nodular slightly low signal intensity in T2WI in 77 cases. The meningeal lesions of all cases had homogeneous or inhomogeneous enhancement in enhanced scanning. There were 85 cases with meningeal nodules, including nodules with scattered distribution in 23 cases, and cluster distribution in 62 cases. The number of nodules was up to 1 105, including 452 nodules with homogeneous enhancement, and 653 nodules with ring enhancement. Most nodules of cluster distribution showed ring enhancement or separate enhancement. Secondary changes included hydrocephalus in 94 cases, anterior cerebral artery involvement in 17 cases, middle cerebral artery involvement in 58 cases, posterior cerebral artery involvement in 9 cases, 42 cases complicated with cerebral infarction and optic nerve involvement in 49 cases. Comparison of MR manifestations of meningeal tuberculosis and meningeal metastasis showed that, the location, type of meningeal involvement, edge of lesions, relative position of lesions and meninges, distribution of nodules were significantly different(P<0.05), except arachnoid lesions (P=0.066). CONCLUSION: The MRI characteristics of meningeal tuberculosis were thickening of cerebral basilar cistern meninges. These signs were valuable for MRI diagnosis of meningeal tuberculosis, including cases complicated with meningeal nodules of cluster distribution. The nodules were of low signal on T2WI, with ring enhancement or separate enhancement, with secondary hydrocephalus, cerebral vasculitis in anterior circulation, and brain infarction. The result also showed that contrast-enhanced MRI was valuable for diagnosis of meningeal tuberculosis as well.

[Analysis on 23 cases of spinal meningeal tuberculosis by magnetic resonance imaging].

OBJECTIVE: To explore the imaging features of spinal cord and spinal meningeal tuberculosis by magnetic resonance (MR). METHODS: We analyzed retrospectively the features of MRI in 23 patients with spinal cord and spinal meningeal tuberculosis compared to 25 patients with spinal cord meningeal metastatic carcinoma. All patients were admitted in our hospital from Jun. 2011 to Oct. 2014. There were 12 males and 11 females with a median age of 26 (range 16-50) years in the spinal cord meningeal tuberculosis group, and 18 males and 7 females with a median age 56 (range 44-78) years in the spinal cord meningeal metastatic carcinoma group. All patients underwent MR plain and contrast-enhanced scanning. The enumeration data were compared with the χ² test and the measurement data were compared with t test. The difference was considered statistically significant when the P value was <0.05. RESULTS: Of the 23 cases, 16 were spinal meningeal tuberculosis and 7 were spinal cord tuberculosis. The MR imaging features were as follows: (1) Spinal meningeal tuberculosis: Irregular and linear strip and hummocky thickening (thickness <5 mm) of the meninges (dura, arachnoid and pia mater), with the average length of involvement of 7 vertebral segments. Enhancement was present in all cases by contrast-enhanced scanning, including clustering or moniliform enhancement in 5 cases. Subarachnoid irregular stenosis was seen in all cases, partial occlusion in 5, abnormal heterogeneous signal in 20, rough cerebrospinal fluid (CSF)-spinal interface in 10, and formation of secondary arachnoid cyst in 15. (2) Spinal cord meningeal tuberculosis: of the 7 cases, 4 showed ring enhancement and 3 showed small plaque with heterogeneous enhancement. (3) There were 20 cases of meningeal metastatic carcinoma and 5 cases of meningeal metastatic carcinoma with spinal cord metastasis. Nodular thickening was present in 8 cases, plaque thickening in 10, and nodular and plaque thickening in 7. Continuous thickening involving 3 vertebral bodies was seen in 19 cases. Multiple localized thickening was present in 6 cases, with obvious enhancement in the meninges and heterogeneous enhancement in the spinal cord. CONCLUSIONS: The MR imaging features of spinal cord meningeal tuberculosis include continuous meningeal thickening, secondary arachnoid cyst, rough and moniliform CSF-spinal cord interface. Diagnosis and differential diagnosis can be made based on these features combined with clinical data and disease history.